Torstenson War

The Torstenson War occurred from 1643 to 1645 within the context of the Thirty Years' War. By 1643, having scored a series of successes in the war in Germany, Sweden felt that the time was right to settle old scores with Denmark. Sweden opposed being forced to pay the "Sound Dues" toll for use of the strait between Sweden and Denmark, and the Swedes also sought to reconquer southern Sweden from the Danes.

Lord High Chancellor Axel Oxtenstierna, convinced that Sweden was militarily able to defeat Denmark, sent Field Marshal Lennart Torstenson to march against Denmark. Proceeding from Moravia, his forces entered Holstein on 12 December 1643 and occupied Jutland in January 1644. In February, the Swedish general Gustav Horn with an army of 11,000 troops occupied the Danish provinces of Halland and Scania in Sweden, although the fortress town of Malmo held out. Denmark was caught poorly prepared, but King Christian IV of Denmark placed his confidence in the Danish Navy to defend the home islands, winning the Battle of Colberger Heide on 1 July 1644 and the Battle of Fehmarn on 13 October 1644. The Danish possession of Norway, governed by Hannibal Sehested, then proceeded to invade Sweden, diverting Swedish troops from their invasion of Denmark. However, the Danish forces were so exhausted that they were forced to accept mediation from France and the United Provinces. In the 13 August 1645 Second Treaty of Bromsebro, Sweden was exempted from the Sound Dues and acquired Jamtland, Harjedalen, Idre, Sarna, Gotland, Saaremaa, and Halland from Denmark. Danish efforts to reverse the loss of its dominance in the Baltics led to the Second Northern War, the Scanian War, and the Great Northern War during the next half-century.